This invention relates to liquid, low-foaming nonionic surfactants, and more particularly to liquid, low-foaming nonionic surfactants having superior wetting properties and generally good scouring and detergency characteristics prepared from aliphatic alcohols having 7 to 11 carbon atoms by the sequential addition of propylene oxide and then a random mixture of ethylene oxide and propylene oxide.
Nonionic surfactants are widely used in commercial and household applications where advantage is taken of their superior performance as a wetting agent, their detergency and scouring characteristics as well as their adaptability for being combined with other types of surfactants and resistance to hard water conditions. Although nonionic surfactants as a class are generally low to moderate "foamers", they foam too much for many applications which involve vigorous agitation.
In recent years a number of nonionic surfactant products have been developed and used commercially which are designated as low-foaming or "controlled-suds" surfactants. Generally, when the need for foam suppression is of prime importance, the nonionic surfactants heretofore developed to meet this requirement have been found to have sacrificed other desirable characteristics and a need exists for materials which exhibit a wider combination of surfactant characteristics than is possible with known low-foaming nonionic products.
Surfactant properties and performance characteristics that would be desirable for many applications, in addition to foam suppression, are, for example, good scouring and/or detergency, being a liquid at room temperature, superior wetting action, and in general, low cloud points, and the development of a material which exhibited a combination and suitable balance of these factors such as superior performance in some or all of these areas while performing adequately in the others would be highly desirable.
It has long been the practice to prepare nonionic surfactants by the addition of ethylene oxide or mixtures of ethylene oxide and propylene oxide to various alcohols, which are generally long-chain monohydric alcohols. Numerous different adducts have been prepared, some of which contain only oxyethylene groups while others contain a random distribution of oxyethylene and oxypropylene groups or discrete blocks of polyoxyethylene and polyoxypropylene. For example, in U.S. Pat. Nos. 3,101,374 to Patton., 2,674,619 to Lunsted, and 2,677,700 to Jackson et al. are disclosed compositions which are prpeared by the addition of varying proportions and mixtures of alkylene oxides to reactive hydrogen compounds such as alcohols. More recent patents, such as for example, U.S. Pat. Nos. 3,770,701 to Cenker et al. and 3,956,401 to Scadera et al. disclose surfactant compositions prepared by the addition of specific proportions of ethylene oxide and propylene oxide to straight-chain aliphatic alcohols having 8 to 20 or 7 to 10 carbon atoms. The compositions disclosed in each of these patents are described as being biodegradable liquids which exhibit high detergency (U.S. Pat. No. 3,770,701) or low-foaming (U.S. Pat. No. 3,956,401) but it is not shown by either patentee that any of the compositions provide a combination of these properties or of other desirable surfactant properties such as superior wetting, nor, from the teaching thereof would one skilled in the art expect these patented compositions to exhibit such a desirable combination of properties.